Tunable Visible/NIR Dual‐Narrowband Organic Photodetectors with Photomultiplication for Interference‐Resistant Optical Communication

ABSTRACT The ability to detect narrowband optical signals is important in optical communication, precise target identification, etc. This study proposes a method to achieve dual‐narrowband visible/NIR detection with gain based on the synergistic regulation of optical and electrical properties of a single device. The device integrates two distinct bulk‐heterojunctions (BHJs), one with visible and the other with NIR absorption, in a back‐to‐back configuration. This design enables bias‐switchable visible/NIR dual‐band detection with photomultiplication, which is controlled by regulating carrier injection from the external circuit. Furthermore, by incorporating an optical microcavity to modulate the light field distribution, tunable visible/NIR dual‐narrowband photodetection is achieved, with a capability to switch the two wavelengths by changing the polarity of bias. For example, narrowband responses at 450 and 810 nm are achieved, where the two modes can be switched by changing the bias polarity. A peak external quantum efficiency (EQE) of 1050% is obtained at 450 nm with a full width at half maximum (FWHM) of 50 nm. A peak EQE of 130% with an FWHM of 75 nm is observed at 810 nm. Notably, this device demonstrates excellent performance in anti‐interference optical communication, operating without the need for additional optical filters.